Method of forming crown caps



Aug- 24, 1948- J. w. EKsTEDT ETAL uETHoD or Fomuue cnowu ons Filed Mayll, 1943 2 Sheets-Sheet 2 Esca-....7 fa

J. W. EKSTEDT ETAL METHOD OF FORMING CROWN CAPS Aug. 24, 1948.

Filed May 11, 194s a xm e W W 'Patented Aug. 241 1948 1 ""Ma'rnon vor roWING n, l "narrow,imn,nionansaertnruy, i v *Y suman.; Y A l, Y-appucaunnjmayin mensen-al Nana-53s Y' jzbniha. (sa-sar" ,j l A 2 Thisinvention relates toa method oi forming Figure iiisaplan viewof a blankfrom which a thermo-plastic'crown cap upon a bottleor the thecapisformed; f i like. n l l `lligure 5 isanl enlarged transversevertical sec- An important object of the invention is to tion throughthe completedcap as applied to provide a method of the above mentionedchar.- 5 a hottie, i A ,A l .f i acter, for forming la thermo-plasticcap inplace '.'Flgure'- isaxcentral vertical section through upon abottle.. fromV a nat blank, and effecting the cap forming meansmatsbroken away, showthe operation quickly and economically. ing iihe.ublank held in the inclined position, .prior A further object of theinvention is to provide to engagement with the bottle, i i a method forrapidly `feeflingfnby gravity the .10 Figure 'I` is a similarview,zshowing the 4bottle heated .thermo-plasticblank to a positiontorbe raised and the `blank shifted'to the horizontal engaged by thebottlewhenjthe bottlefxrisespand positionfpriorto". the formingoperation, to compensate `for the rebounding actionffoffme r `vFigure!!is a similar view," showing the" blank falling blank, prior-ato .itsengagement withithe forced upwardlyintotheforming dieyand showbottleY ,ff 1y v n 115 in! the forming and drawing step." A furtherobiectfoitheinvention-=is:,toprovide v Iig\ire,.!l is asimilarview,.showin`g the-cap a `method of the above lmentioned::characterformedupon'the bottleandfstripped from'the which producesa pressing/anddrawingraction forming dieux` f 'f f il riff upon the skirt ofthethermo-plastic,` cap'-1being ffIn` .therdrawings,v'whereintforfthepurpose of formed=thereby causing the-cap to retainrac- 29 illustration:is lshownfafpreferred i'ormof appacurately its shape `uponfhardeningmndpreserve ratus for the practice of the method, the numeral ingv itsbinding Ior contacting-engagement with Il:designatesfza'l'verticalistationaryreylindrlcal the bottle." i f fr n;is @1, 1 u sleeve, receivingfthereinw'aresllientfelement Il, A further.object .ofhe invention is` to.A provide which,I may bein zthefiorm cof arubber-plug,haw a method toeiorce:.theinnel*portionE of. theacap 2,5ingthe desiredstiilnessfto exertl'a'suitablefdowninto contactwiththezinner portion oithecbottle', wardgtorce.c=Thisfiorcefniaybefrom"10lbs.`to`250 when the capis xformedandsapplied to the bottle.lbss'pei-.v'square inch.: The"tenslonof therubber x A further`objectvoffthe inventionv isto provide plug mayfbelvariedbyadjustingaplugibhaving a method-havingwa drawing action.=uponfrthe screwrf threaded:lengagement-.withirrthe" top"`of skirtof,theeheatedfthermo-plasticcapilwhereby -r'o the sleeve, andffhavingapolyonalf` headliby the thickness.-.of-` the sKkirtis reducedandl'aethickmeans of which it mayl be trned The'sleeve ened extensionformed ator nearxthe bottoinfof il is preierablyfiormed'ofrmetaland!isprovided the skirt, for interlocking` .engagementwith the at its:lower end withfanrannular recesswil, formheini-0fthebottle;` ai, c; ,fring1 a;horizontalshou1der\II; Arrangedmeneath A furthenobjectohe-inventionisstotprovide 35 thesleevef-iliis al centering! or fholdingdevicepina method di thefg-alziovea-v mentioned character cluding i' aLiverticalisleevez f: Il, alsoifpreferably which strips f the ihardenedpiformed .cap :,uponl the formed f of; metal;` and the: sleevelllsby bottle from :witliin theav-vforming'fdieg, iter he screws -IJf.or ,theifiikei @This sleevellfhas'ari comp1etionofthe operations.-ff'ya y uppereylindricalwborefllpwhichisf considerably A further objectieftheinventi v,i;o p1'ovide` $9 Smaller -iniidiaxnetenthan` theborefofutheizrecess a thermo-plastic; capf-which'millabe securely.- heldl l ,'f;and;he nce;,the sleeve :1li: forms: asholdera, upon the`bott-,le and` atiord1 argus tight` Joint;4 v-

arrangedifoppositef the; shoulder` :iii: ,'I'hex` sleeve v andgdygnmesjjff .the `jfwhelitlgx), l hs fa' 10mn-cylindrical :b0l'e12l,:h`avlngl` ,a-cbll will be; apparentd `ngithecourse lie followysiderably y smaller, i diameter thanthe;.,rbo1ie fil; 1,8 deSQriPO!!nuff: e fai 45 and fformln'gaawerticallyf inclined;` shoulderflll.,Infthe ancornpanyingdraivixu;` A orrningaa ThisYvertically-inclined;shouldersextends:"downe 0f this, iplliiimbanm inywhichflikef numerals wardlygin the; directiomoi-travel: of theiblankftb are employedft d be=descrlbedi,=f-Thef;sleeve 4lhhasavedownwardly flaring? recess Ilka leadingr-intofathe ybore.` En, as Y 1i t v i, mwnm,Awertically,afinclinedcfslot ,-:22 is/.formedapparatnsemployedinthe-practican! .the method, inthe sleeves t Iliandeilfandlleads into--the bore n, sure2fis, ahorizontalsection takenyon ne Il,` atthehigh endnoi-f,thevshoulderfll ,and the 2.--2 o fF.igurel, K L` bottom.off-thisslot-4is'acontinuation,ofstheshoul-JFiguren? isla similar view takennoniiineaif-J derllfu Y against movement-is a forming and drawing die 22, preferably formed of metal. 'Ihis dieis annular and has a vertical bore 24 which is circular in cross sectionand tapers slightly upwardly. The taper extends from the top of the bore24 to a rounded outwardly flaring shoulder 2S. The extent of the taperispreferably .010" (ten thousandths of an inch).

Mounted for movement within the die 22 is a forming plug 26, preferablyformed of metal, and this plug has substantially a sliding fit withinthe die 22. The plug is provided at its bottom with a reducedcylindrical extension 21. At its top, the plug 28 has an enlargedportion or flange 28, which engages the top of the die, to limit thedownward movement of the forming plug.

lThe elements 21 and 28 are preferably formed integral with the plug 26.The enlarged portion 28 is engaged by the rubber plug il.

Arranged at a suitable elevation above the sleeve Ibis a heatingunit-29, preferably lhorizontally disposed. This heating unit has aplurality of spaced fins I3i), forming pockets to receive blanks Si ofthe thermo-plastic material. This heating unit is turned or indexed sothat the heated blanks, one at a time, are discharged in succession intothe upper end of a vertical chute 32 having a lower inclined portion 33,in communication with the inclined slot 22.

Arranged beneath the sleeve i6 is a vertically movable plunger 35,supporting a bottle I6 to be raised and lowered thereby. This plunger isin-V eluded in the conventional bottle capping ma chine, wherein theplunger is raised to elevate the bottle during the crowning or cappingoperation. The bottle has a neck 3l and is provided at its upper endwith a bead 2l. This bea-d has an inner transversely convex surface I9and an outer transversely convex surface Il and a reduced portion orrecess l'l beneath the bead.

The blank 3i is formed of thermo-plastic ma terial, and we preferablyfor-m the blank 3| of cellulose acetate, or a cellulose acetatecompound, although other thermo-plastic materials may be used, such asthose recited in our copending application for Thermo-plastic crowncaps, method of forming the caps, and method of applying the caps tothebottles,l led November l1,

1942, Serial No.- 465,258 which became abandoned on October 12, 1947.

The practice of the method is as follows:

The bottle `36 is placed upon the plunger and is held in the loweredposition. The heater I! is preferably maintained at a temperature ofsubstantially 340 F. and is filled with the cellulose acetate blanks 3|which are heated .to substantially 340 F. The heater I0 is then turned astep and the circular blank 2i, at substantially 340' F. drops from theheater and is supplied to the chute 22 and falls by gravity instantlythrough the chute and passes through the inclined slot 22 and enters thesleeve I6 and rests upon the inclined shoulder 2|. The invention is not-restricted to heating the blank 3i to 340 F., as the temperature mayvary from 250 F. to 340 F. for the cellulose acetate blanks, and for theother thermo-plastic blanks. `It is sumcient to heat the thermo-plasticmaterial so that it will be moldable. There is some tendency for theblank 3| to rebound slightly, when reaching the lower end of theshoulder 2l, and when this occurs, the blank instantly returns to thelowermost position by gravity, since it slides down the inclinedshoulder. As soon as the heated blank 3|. iS. in

4 .f the lowermost position upon the inclined shoulder 2|, the plungerIl is moved upwardly. As the bottle is elevated its neck enters the bore2l, beneath the blank Il. and the bore 2l will serve to center thebottle, if necessary, Figure 6. As the bottle continues to moveupwardly,'the bead 20 engages with theheated blank Il and shifts theblank to-a horizontal position, Figure 7, and causes the', blank to moveupwardly with the bead, .the bore Ii serving to center the blank uponthe bead. Further upward movement of the plunger 'Ii and bottle 2lcauses the marginal portion of the blank Il to engage with the roundededge 2l, whereby such marginal portion is folded or formed -downwardlyabout .the outer face II of the bead. The continued upward movement ofthe bottle and blank Il causes the bead 2l and blank 2| to Dass into thebore 24 of the die 23, e

Figure 8.

The upward movement of the blank Il is opposed by .the forming plug 2l,pressed downwardly by the, rubber plug il. This forming plug 26therefore exerts a downward yielding pressure upon the heated blank 3land securely presses the upper portion of the blank against the top Vofthe bead 2l, while the extension 21produces a depression or recess 42 inthe top of the blank and causes the outer portion of this depression .tobe forced into engagement with the inner convex face 2| of the bead 2l.As the heated blank-3i is forced upwardly into the forming and drawingdie. 2l, while applied to the bead 2l, its marginal portion is foldeddownwardly over the cuter convex face 40 of the bead. forming a skirtportion 43, of reduced thickness and providing at the bottom of theskirt portion a locking portion 4I of increased thickness. The upwardmovement of the bottle and blank 2i into the stationary die 23, causesthe material of the skirt portion 4l .to be drawn axially anddownwardly, as well as forced inwardly against the convex face 4I of thebead. This downward drawing of the material at the skirt portion I3 insome way changes the molecular arrangement or con` dition of the heatedthermo-plastic material whereby the formed cap, upon cooling, willretain its precise shape. particularly at the skirt portion, and thisskirt portion will remain in firm contact with the outer face Il, thusinsuring a gas tight lit, and holding the cap in place upon the bottle.yIt may be that the phase of the thermoplastic material at the skirtportion due to the drawing action, has been somewhat changed, or itv maybe that the thermoplastic material at the skirt portion has been drawnor stretched beyond its limits of elasticity. Whatever may be thereason, it has been found that the drawn skirt portion Il will retainits identical shape and size upon cooling, or becoming solid. This is animportant feature of the invention, as the diiilculty encountered in theuse of .the ordinaryv pre-formed thermoplastic crown cap, is that after-viding a joint which is not gas tight. Since the transverse thicknessof the skirt 43 is reduced by the drawing action, the excessthermoplastic material is drawn downwardly below the maximum exteriordiameter of the bead Il or convex face 4l, providing a locking portionor shoulder Il of increased thickness. upon the lower end 0f the skirtportion. This thickened lock- "clearlyf' shownin Figure i5. "th

'in'l thickness downwardly' tially o'f inch inl thic greater lthan thatof" the topo Q i would depend somewhatupon fthe contourof 5 ing portionMtbeneathaw'tbeadsll, serves to securely attach the crown canto thebottle., f a

a thickness at its top or subst tiany ,1.

shoulder or portion Il is .The `locking portion 'Il' may t.

the neck 'of the bottle. In" order that the top of the cap would have athickness of of an inch the original blank 3i would have a thickness ofY of an inch. The die 2l is provided with a bore 24 having a diameterequal to the maximum exterior diameter of the bead Il plus one thicknessof the blank 3i. The cellulose acetate blank 3| is heated tosubstantially 340 F. and applied to the bottle and formed thereon atsubstantially this temperature to produce the crown cap. The formingoperation is effected continuously and quickly by the upward movement ofthe plunger 35 and the associated forming means. The upward movement ofthe bottle is effected by the same means and in the same manner asoccurs in the conventional crown capping machine. When the bottle ismoved upwardly there is a relative axial movement between the die 23 andthe bottle lwhich is inwardly toward the longitudinal center of thebottle. Since the diameter ofthe bore 24 of the die 23 is equal to themaximum exterior diameter of the bead Il plus one thickness of the blankIl, the reduced portion of the skirt will be half the thickness of theoriginal blank. Before the blank Il is formed it is fiat and extendsradially beyond the maximum exterior diameter of the blank. When thediameter of the blank is reduced, such reduction in the diameter adds tothe thickness of the blank at its marginal edge, and since the blank isfolded to produce the skirt at the same time that its diameter isreduced, the increase in thickness occurs in the skirt'and thisthickness increases toward the marginal'or free edge of the skirt. Theskirt is pleated or folded but the pleats or folds do not show since thematerial is plasticized and the skirt appears integral. The thickenedportion 44 is formed to some extent by the material which is obtained bythe thinning of the reduced portion of the skirt. The thickened portionM remains considerably beneath the maximum exterior diameter of thebead. The drawing action is axially or longitudinally of the bottle, andinwardly or toward the longitudinal center of the bottle. When used inthe description and claims the term axial means longitudinally of thebottle. The term "axially inwardly" means longitudinally of the bottletoward its longitudinal center. Alfter the forming operation iscompleted, the plunger I5 has a dwell at its top position for about 3 to3l/2 seconds, which is suilicient to allow the thermo-plastic materialto cool and harden. After this, the plunger Il is moved downwardly andthe forming plunger 1s moved downwardly by the rubber plugI II andfollows the formed cap. The forming plug Il now moves into the die 23and strips the formed cap from the die. The completed cap is thereforeapplied to the bottle and separated from the die. The die 23, plunger 20and contacting elements a-re all at atmospheric or room temperature.

We also ilnd that by the use oi a thermowhich` moves downwardlyandfornis the thickened locking-"portion of th`e cap, which lockingportionis arran'gedwithin the recess Il, and securely holds the cap tothe bottle. Further, the extension 21 forms the recess 42 at the top ofthe cap, which recess stiiiens the cap, and this also causes the outerportion of the recess to be pressed outwardly and firmly engage theinner convex face Il of the bead. The invention is not restricted to theuse of the cellulose acetate blank or thermoplastic blank having athickness of of an inch, as this thickness may vary somewhat. Thethinness of the skirt is not restricted to s of an inch or half of thethickness of the blank, as the thinness of the skirt may vary, but thereis a reduction in thickness at the skirt, which results from the drawingaction, and produces the excess material to provide the thickenedlocking part.

It is to be understood that the form of our invention herewith shown anddescribed is to be taken as prefer-red examples of the same,` and thatvarious changes in the shape, size, and arrangement of parts may beresorted to Without departing from the spirit of our invention or thescope of the subjolned claims.

Having thus described our invention, what is claimed is:

l. The herein described method of forming a blank to apply a cap upon abottle or the like provided with a bead having a maximum exteriordiameter, comprising taking a substantially circular blank formed ofthermoplastic material and having a greater diameter than the maximumexterior diameter of the bead and heating such blank so that it may beformed and drawn, applying the heated blank tothe free end of the beadin substantially concentric relation thereto so that the marginalportion of the blank extends radially beyond the maximum exteriordiameter of the bead, forming the marginal portion of the blank aboutthe outer side of the bead to provide a skirt portion surrounding thebead and extending axially and inwardly beyond the maximum exteriordiameter of the bead, subjecting the skirt portion adjacent to themaximum exterior diameter of the bead to an` axial and inward drawingaction and thereby reducing the thickness of the skirt portion adjacentto said maximum exterior diameter and maintaining the outer face of theskirt portion and having a greater diameterthan the maximum exteriordiameter oi the bead and heating such blank so that it may be formed,applying the heated blank to the i'lree end of the bead in substantialconcentric relation thereto so that the marginal portion oi' the blankextends radially beyond the maximum exterior diameter of the bead,eiecting a relative movement in a direction axially of the bottlebetween the bottle and a rigid tubular die having a. 'substantiallycylindrical bore which bore has a diameter equal to the maximum exteriordiameter of the bead plus substantially one thickness of the blank andcausing the blank and bead to enter the bore, and allowing the i'ormedcap to harden and removing the cap from within the bore.

l JOHN W. EKBTM.

ALBERT F'. PITYO.

ammore crrnn The following references are of record in the file of thispatent:

UNITED STATES PATENTS Number Name Date 1,114,323 Westlake Oct. 20. 19141,8635081 Bellows June 14, 1932 2,187,190 Wilcox Jan. 16, 1940l2,210,250!) Strauch -e-., Aug. 6, 1940 `2,325,309 DeSwatt l--.- July27, 1043 2,431,114 Golding Nov. 18, 1947

